1. Field of the Invention
The present invention relates to a dissipating device, and more particularly to a dissipating device that is used to build a high efficiency radiator for dissipation by natural convection for cooling a CPU (central processing unit) or an IC (integrated circuit) die at low cost.
2. Prior Art
For keeping a CPU or an IC working in a normal temperature range, a radiator is attached thereto. In accordance with the methods of removing heat from a CPU or an IC while it is working, one of two ways is used. One method uses a forced draft cooling system, and the other is the use of convection. The conventional radiators have the following types:
1. a dissipating block and gum for increasing the thermal radiating area. The dissipating block is made with several ribs or vertical needles, with a material of high thermal conductivity, and adhered on the surface of a CPU or an IC die with gum to radiate the heat emitted from the CPU or the IC die to the air;
2. a cooling fan attaching on the surface of a CPU, or cooperating with above-mentioned dissipating block to combine a forced draft cooling radiator to direct a flow of air; and,
3. a heat pipe coupled to the surface of a CPU, the heat of the CPU is removed.
With regard to use of a cooling fan, a power supply is needed, vibration and noise are generated as it runs, and it increases the power supply load, especially if many cells operate at the same time. The dissipating effect of the dissipating block and gum or the heat pipe is limited, especially without the cooperation of other dissipating devices, so the heat dissipation efficiency is not high enough. On the other hand, the dissipating block is made of an inferior aluminium (Al) extracted from waste metals, and the surfaces of it should be treated by an anti-corrosion process with a chromate treatment, which bears some toxins that will be harmful to humans when heated. Additionally, the molded aluminium bar should be cut into the plates by a high-pressure water cutter, and finished with an anodize finish for increasing the corrosion resistance and dissipating effect. For obtaining a better dissipating effect, a bigger area of the cutting surface (facing to the air) is provided, and the longer the cutting time is increased. The whole block would thereby be heavier, so the production cost is increased. Additionally, the above-mentioned two types of anti-corrosion treatment for aluminium dissipating blocks may cause pollution to the environment.